Amanita muscaria, and closely related fungi (i.e., Amanita pantherina, Amanita muscaria variant formosa, and others within the Amanita genus) contain substances that are GABA analogues and antioxidants. For example, according to at least one study, Amanita species were found to have “the highest antioxidant activities” among mushroom species tested.1 However, when fresh tissue is ingested, even small amounts can cause symptoms of gastrointestinal distress (nausea, vomiting, diarrhea), headaches, profuse sweating, hypersalivation, periods of agitation and confusion, followed by coma-like sleep. These negative reactions are generally ascribed to the presence of ibotenic acid within fresh tissue, an excitatory neurotoxin. Although ibotenic acid is a neurotoxin with severe adverse effects at high concentrations, its decarboxylated variant, muscimol, is an analogue of gamma-aminobutyric acid (GABA). GABA and GABA analogues have many health benefits, including anti-aging properties, supporting the production of growth hormone, diuresis, neuroprotection, anti-hypertensive properties, and the promotion of healing.5,6,7 
Fresh A. muscaria typically contains 258 to 471 ppm of ibotenic acid within the entirety of the fungi. Nearly all the ibotenic acid concentrated in the caps, and very little muscimol present.2 Typically, the ibotenic acid to muscimol ratio of fungal cap tissue would be 9:1 or greater in fresh samples.2 While drying of the fungal tissue has been reported to convert a portion of the ibotenic acid to muscimol, such conversion is incomplete and highly variable according to sample variation and conditions. Indeed, a relatively low conversion rate of only 30% is typical by merely drying fungal tissue, leaving an unacceptably high concentration of ibotenic acid, typically 180 to 1800 ppm.3,4 A common ibotenic acid to muscimol ratio would be 3:2 in dried specimens4, such that the neurotoxin amounts far exceed the GABA analogue. Furthermore, ingesting the dried tissue, which contains the relatively indigestible mushroom cell wall component chitin, would result in adverse physiological effects.
Therefore, a method to reduce the ibotenic acid in Amanita tissues, while maximizing water-soluble nutrients, including maximization of the GABA analogue muscimol, from a natural product, would be highly desirable.